A common problem with detergent compositions for use in automatic dish washing machines is that they cause spotting and filming on crockery and glasses during the wash process. The spotting and filming is caused by the deposition of calcium salts.
The spotting and filming is a particular problem when a non-phosphate detergent is used. EP 0 659 874 (Procter and Gamble) recognises this problem and describes a carboxylate based builder system with ethyl 1-hydroxy-1,1 phosohonic acid and an organic polymer.
EP 0 364 067 (The Clorox Company) describes a machine dishwashing composition with alkali metal carbonate as the sole builder, an alkali metal silicate, a low foaming surfactant and a calcium crystal growth inhibitor which may be a phosphonic acid.
The present invention has found that the precipitation of calcium can be mitigated by the choice of chelating agent and builder.
Furthermore, compositions according to the present invention are particularly stable.